Spinster & toyboy

[bluelace]

hey I have
2 female bettas, 1 over 2 years other under 6 mths
1 male betta, around 6 months
Is it okay to breed my older female to a younger & slightly smaller male for if it's the first time either of them have breeed? I've been keeping them all in a heated pond (all seperated of course) and the older female is has acting aggressive while the male flirts with the younger female. Should I condition them both before letting them see each other? Would it be best to mate the youger pair first before mating my older girl with him? Or do I need to buy another male just for my spinster?
I've also heard that fry can get tangled in duckweed & die. Is this true? Should i remove all of it before trying to breed my bettas?
any help appreciated